Figure 2
From: Studies on the basic reproduction number in stochastic epidemic models with random perturbations
Stability modeled using the parameters \(N=1\), \(\beta = 0.8\), \(\sigma = 0.3\), \(\mu = 0.4\), \(\eta = 0.9\), and (a) \(\gamma = 0.85\) and \(\upsilon = 0.7\) (upper right), (b) \(\gamma = 0.75\) and \(\upsilon = 0.7\) (upper left), (c) \(\gamma = \beta \upsilon N \frac{\eta }{\mu (\mu + \upsilon )} - \frac{\sigma ^{2}}{2} \frac{\upsilon ^{2} \eta ^{2}}{\mu ^{2} (\mu + \upsilon )} N^{2} - \mu \) and \(\upsilon = 0.85\) (lower left) and (d) \(\gamma = 0.55\) and \(\upsilon = 0.85\) (lower right). The initial condition is \(( N,0, 0, 0 ) = ( 1,0, 0, 0 )\) for all of them